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AIXpert Blog

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AIXpert Blog is about the AIX operating system from IBM running on POWER based machines called Power Systems and software related to it like IBM Systems Director, PowerVM for virtualisation and PowerSC for security plus performance monitoring and nmon

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I am not making a claim to fame (OK, I am really) but the UK Power Systems Advanced Technical Support group (that is me and Gareth) dropped the term "LPAR" or Logical Partition as a New Years resolution. We like to occasionally test to see if we can influence other IBMers and the IT Industry. We now in 2011 onwards use the terms: Virtual Server - this is the term used by Systems Director for over three years. While I can live with that name but the abbreviation of VS - it just does not feel or sound right. Virtual Machine - this... [More]

This is a follow on to a previous blog on " PowerVM Virtual Ethernet Speed is often confused with VIOS, SEA IVE/HEA speed "- here is a Direct Link I regularly get asked : "I have just heard about this [PowerVM virtual switch | vSwitch | Hypervisor Ethernet Switch] is available but I can't find out any information at all, help!" They are wanting to run two (or more) virtual switches within the one Power machine to completely separate the network packets of groups of virtual machines (LPARs) so they know for sure there can... [More]

Most AIX system administrators use: smitty tcpip to add a hostname, IP address, network mask, gateway and DNS server setting to get the virtual machines (LPAR) and AIX on a network. And as a side benefit so we don't need to use the ghastly VTERM console any more as ssh or the dreaded unsecure telnet (just don't do it) can now be used - as the root user: # smitty tcpip
...
Minimum Configuration & Startup Further Configuration
Use DHCP for TCPIP Configuration & Startup
IPV6 Configuration
Quality of... [More]

Earlier today I received email from a customer reporting their large POWER7 based machines where on firmware 720_64 to 720_90 and their reluctance to take the outage to upgrade it. They were asking for fine details of newer firmware levels and what advantages this would bring to " justify the outage to their user departments ". To be blunt this is a horror story: I lay awake at night in a cold sweat about stories like this. The customer has the whole "running computers plan upside down". The question should be " can... [More]

The documentation for HMC Version 7 says that the web browsers supported are Microsoft Internet Explorer 6.0 and later, as well as Firefox 1.5.0.6 and later. While many users have no trouble with Internet Explorer 7.0, others have reported problems. What makes the difference? Sometimes its Java code, and sometimes its the browser settings. For example, a customer recently reported trouble with IE 7 after he updated Java to jre 1.6.0_05 from jre 1.6.0_03. Previously, IE 7 had worked fine. IBM support usually will make a best-effort attempt... [More]

I spent two days with a "well known brand" UK retailer trying out Versioned Workload Partitions (vWPAR). Actually, it was with an IBM Business Partner that runs the machines for them- two knowledgeable and fun guys to work with - we were asked by the European manager in the next room to keep the noise down! This Versioned WPAR technology lets you run AIX 5.2 or AIX 5.3 inside an AIX 7 on Power7 Workload Partition (WPAR). You simply get the source AIX up to the required level (which you should already by running), then take a mksysb... [More]

The AIX "lru_file_repage" is a new and more flexible memory tuning option that solves the problem of having to limit JFS2 file cache to guarantee memory for applications like databases. It is available starting with AIX 5.2 ML5 and AIX 5.3 ML2. It can be set using the "vmo" command or via "smit tuning => Memory". Here's how it works. AIX classifies memory into two categories: file cache and working storage. Over time, memory use grows with both types of memory. AIX will eventually need to free memory, and it can do so by freeing either file... [More]

I have been using Shared Storage Pools phase 2 (SSP2) on the beta test a lot recently and it works well - I am very impressed. One key side effect of SSP2 is that it really makes Live Partition Mobility (LPM) very simple and safe. But then I hit a problem that stumped me - nothing to do with the SSP2 technology - it was just that I in the Advanced Technical Support group have got rusty in setting up and using LPM. The first problem that most people hit is that the source and target Power machines must have the same LMB size - the what??... [More]

A very nice chart from Richard Milton of IBM on the minimum levels for AIX and VIOS of Power7 and Power7+ hardware. Download as a PDF: AIX_Levels_on_POWER7_Hardware_2013_06_20.pdf We will try to update this as new machines arrive.

﻿ I have been looking at some nmon data from an IBMer looking into a customers machine. The virtual machine (LPAR) is running the Oracle RDBMS with 75 dedicated CPUs - on a POWER7 Power 795 at 4 GHz. The Excel spreadsheet is quite scary at 144 MB thank goodness my Thinkpad has a SSD but not the record by a long way. Too many data save points can ready add u and so too can lots of processes if you are saving process data. Also with 75 CPU and SMT=4 that is 300 Tabs for Logical CPU, 300 for PCPU and 300 for SCPU and that starts to add... [More]

Before we look further in to memory affinity we need to recap on the scheduling of processes and process threads of a multi-threaded process to simultaneous multi-threading (SMT) processors like POWER7. POWER5 and POWER6 had two modes of SMT off (one thread) and on (two threads) - with SMT=on two processes run at the same time (in the same clock cycle) on the CPU-core but using the different logical units inside of the CPU-core (units like the integer maths (there is more than one), floating point maths (there is more than one), compare and... [More]

Installing Open Source on AIX systems can be a little .... um .... frustrating and I have just been round that loop with installing Ganglia the excellent Performance Monitoring tool to demonstrate it and actually use it too on my own servers. The hard bit is that for every Open Source program, that you want to install, there is 10 to 20 prerequisite packages that you need to install first and you go round this the loop four times as the prerequisites have prerequisites .... This has got known as the "RPM dependencies form... [More]

Having just done this and getting questions on it from customers, I thought I should share a few notes: 1) The process is nicely documented and you need to follow the instructions. I recommend using the Release Notes as a check list as missing out a stop causes the next bit for complain or fail. Fortunately, the recovery is just doing the bit I missed. 2) Read the Release notes - even better print them out and cross them off as you go: http://www.ibm.com/support/docview.wss?uid=hpc1vios117f5701 - upgrade to 2.2.2.1... [More]

We all know that a VIOS level is only fully supported for 2 years ... right! If you have problems with an older VIOS, you may be asked to upgrade to a supported level before a fix can be issued. Most teams run a dual VIOS configuration to allow painless and live upgrades for just this reason. The other reason is to survive a VIOS crash but I have never had a VIOS failure but that would be because I don't go fiddling with them nor adding unsupported software. I quickly upgraded my POWER7 VIOS from 2.1 to the latest VIOS level and made a... [More]